Please consider the following image:
I know when I use a:b in @constraint it means an array from a to b. I need to code the arrays like {a_j,b_j} in @constraint of the mentioned code. Can you please help me to code that?
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You need to provide more information: stackoverflow.com/help/minimal-reproducible-example. Here is the JuMP documentation: jump.dev/JuMP.jl/stable/manual/constraintsOscar Dowson– Oscar Dowson2021-10-04 00:32:23 +00:00Commented Oct 4, 2021 at 0:32
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Does this answer your question? Dependent Arrays in Constraints JuMPOscar Dowson– Oscar Dowson2021-10-08 01:44:45 +00:00Commented Oct 8, 2021 at 1:44
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2 Answers
I understand that you are asking about a custom indice iteration over a single constraint. This can be done in JuMP as:
using JuMP, Cbc
m = Model(Cbc.Optimizer)
@variable(m,x[1:3,1:3]>=0)
@constraint(m, con[ (i,j) in [(1,2),(2,3),(3,3)] ], x[i,j] >= 5)
Let us have a look what we got:
julia> println(m)
Feasibility
Subject to
con[(1, 2)] : x[1,2] >= 5.0
con[(2, 3)] : x[2,3] >= 5.0
con[(3, 3)] : x[3,3] >= 5.0
x[1,1] >= 0.0
x[2,1] >= 0.0
x[3,1] >= 0.0
x[1,2] >= 0.0
x[2,2] >= 0.0
x[3,2] >= 0.0
x[1,3] >= 0.0
x[2,3] >= 0.0
x[3,3] >= 0.0
Comments
A key point to understand is that--unlike AMPL and GAMS--there is no specialized syntax for constructing and managing sets in JuMP. Instead, you can use any available Julia syntax and datastructures.
Examples:
using JuMP
N = 10
model = Model();
@variable(model, x[1:N]);
@constraint(model, [s=1:3], sum(x[j] for j in 1:N if mod(j, s) == 0) == 1)
using JuMP
N = 10
model = Model();
@variable(model, x[1:N]);
d = [Set([1, 2, 3]), Set([2, 4, 6])]
a = [Set([3, 4]), Set([5])]
J(s) = [j for j in 1:2 if s in union(d[j], a[j])]
@constraint(model, [s=1:2], sum(x[j] for j in J(s)) == 1)
1 Comment
Mahsa
I tried both codes. But they do not work in my case. d and a are both subsets of set S in the size of N. For example: (N=5, T=3, S=6), j=1:N, t=1:T, s=1:S.
d=[1,2,2,3,1] (the elements of d are the first 3 digits of S and the size of d is N) and a=[6,4,5,6,4] (the elements of a are the 3 last digits of set S and the size of a is N). Now I want to code that the index s is starting from d and ending with a. It is like this s[j=1]={1,6}, s[j=2]={2,4}, s[j=3]={2,5}, s[j=4]={3,6}, s[j=5}={1,4}